Understanding Tsunamis
Source: Japan earthquake triggers tsunami warning: What is a tsunami, why does it keep forming in the island country? (The Indian Express, January 2, 2024)
On January 1, a powerful 7.6-magnitude earthquake struck Japan’s north-central region, triggering tsunami waves that battered multiple coastal areas.
- How Tsunamis Form: Tsunamis are formed by underwater earthquakes or volcanic eruptions. These events can move the sea floor and displace massive amounts of water. This displacement generates waves.
- The Role of Ocean Volcanoes: Ocean volcanoes also contribute to tsunamis. As they erupt, lava forces water outwards, creating waves.
- Tsunami Dynamics: NASA explains that tsunamis start in the deep sea. Here, they can shift huge volumes of water. Nearing land, these waves increase in height due to shallower ocean depths.
- Speed and Size: Tsunamis can grow to several hundred feet and may reach speeds matching jets over deep seas. In shallower waters, their speed drops.
- Factors Affecting Tsunami Formation: Many factors determine if a geological event causes a tsunami. These include the sea floor’s shape and the quake’s location and magnitude.
Earthquake and Tsunami Risk in Japan
- Location and Tectonic Activity: Japan is located on the ‘Pacific Ring of Fire’, the most earthquake-prone area on the planet.
- The ‘Pacific Ring of Fire’: The ‘Ring of Fire’ is shaped like a horseshoe around the Pacific Ocean. It’s where many earthquakes and volcanoes are triggered.
- Interacting Plates: In this zone, the Pacific Plate, Eurasian Plate, and Indo-Australian Plate often collide. Such movements lead to natural disasters like earthquakes and tsunamis.
Understanding Radiocarbon Dating
Source: How radiocarbon dating revolutionised science (The Hindu, January 2)
- The Basics of Radiocarbon Dating: Radiocarbon dating measures the age of objects. It uses a special type of carbon called carbon-14.
- Formation of Carbon-14: Cosmic rays create carbon-14 in the atmosphere. These rays come from space and hit atmospheric gases. They release neutrons that turn nitrogen into carbon-14.
- Carbon-14’s Journey: Created continuously, carbon-14 binds with oxygen to become radioactive CO2. Plants absorb it, and then animals eat the plants. This is part of the carbon cycle.
- What is Carbon-14?: Carbon-14 is a type of carbon that living things have in their bodies. It mixes with other types of carbon while they are alive.
- Life and Carbon: When living, a body uses carbon. It breathes it in, eats it, and loses it through skin and waste. Carbon-14 is part of this cycle.
- Death and Carbon: When something dies, it stops taking in carbon-14. The carbon-14 it has begins to decay over time.
- Measuring Time: Scientists measure how much carbon-14 is left to find out when the organism died. They compare it to what we expect to find theoretically.